The objective of the project is to determine the demographic, socio-economic and biophysical factors affecting the intensity of land use by migrant colonists and indigenous populations in the Ecuadorian Amazon. Data on colonists collected in an earlier project will be complemented by new data collection in indigenous areas. The data analysis compares and contrasts behavior and determinants between colonist and indigenous populations and among four indigenous groups, which differ in size of territory, population size and density, and degree of integration into the market economy. Drawing upon the theoretical perspectives of demography, landscape ecology, and political ecology, we develop a conceptual model which links the demographic, biophysical, and socio- economic factors influencing land use to an intensity of land use gradient. An ethnographic study in five indigenous communities will be carried out to study the attitudes, beliefs and behaviors pertaining to population and land use, and to inform the development of survey questionnaires. Using this model, we will (1) measure the demographic (household size and composition), biophysical (land quality and availability), and socioeconomic (property regimes and access to key infrastructure) factors for colonists and indigenous populations through household and community surveys; (2) use Global Positioning System (GPS) receivers to identify dwellings, agricultural plots, and land use; and (3) process satellite imagery to determine land cover types, land use patterns, landscape features and infrastructure. The geo-referenced socio-economic, demographic, and biophysical data will be integrated within a geographic information system (GIS) in order to derive measures for multi-level statistical models of the determinants of land use intensity. By integrating data collected from both native residents and migrant settlers, this project provides essentially complete overage of land use in the northeastern Ecuadorian Amazon, and tests general hypotheses which elucidate land use patterns in other parts of the world. The Ecuadorian Amazon, one of the proposed primary Pleistocene forest refugia (Haffer, 1969), is an area of extraordinary plant and animal diversity and endemism. Ecuador is losing about 1.8 percent of its Amazon forests per year-the highest loss rate of any Amazon basin country. This region is thus an excellent study site for observing the behavior of rapidly growing populations of small farmers and a diverse population of indigenous peoples in the face of an increasingly densely-populated rainforest frontier.